Controllable valve arrangement for controllable two-tube vibration absorbers

ABSTRACT

A controllable valve arrangement for controlling two-tube vibration absorbers comprises a power cylinder with an interior space subdivided into a first and a second power chambers by virtue of a slidable piston, and with a balancing chamber partly filled with oil. A valve body is actuated by an electromagnetical transducer and prestressed by a spring. The valve body influences a hydraulic connection through which a unidirectional flow is passed. In a traction stage, a unidirectional flow exists between the first power chamber, on one hand, and the second power chamber jointly with the balancing chamber, on the other hand. In a thrust stage, a unidirectional flow exists between the first power chamber jointly with the second power chamber, on one hand, and the balancing chamber, on the other hand.

FIELD AND BACKGROUND OF THE INVENTION

The present invention is generally related to a valve arrangement for acontrollable two-tube vibration absorber, and more particularly, to avalve arrangement for a controllable two-tube vibration absorber with apower cylinder whose interior space is subdivided into a first and asecond power chambers by means of a slidable piston, and with abalancing chamber partly filled with oil. The inventive valvearrangement includes a valve body which is actuatable by anelectromechanical transducer and prestressed by means of a spring. Theaforementioned valve body influences a hydraulic connection throughwhich a unidirectional flow is passed. In the traction stage, theunidirectional flow exists between said first power chamber, on onehand, and said second power chamber jointly with said balancing chamber,on the other hand. In the thrust stage the unidirectional flow existsbetween said first power chamber jointly with said second power chamber,on one hand, and said balancing chamber, on the other hand.

A valve arrangement generally related to the present invention is knownfrom the older, not anticipated patent application of this applicant,No. P 41 08 026.2. The valve arrangement of the vibration absorber shownthere is configured as a single-stage slide valve. The position of thevalve slide depends on the hydraulic pressure differential coming aboutacross the slide valve, the volumetric flow rate passing through thevalve, and the actuating current of the electromechanical transducer.

The prior-art valve arrangement has the disadvantage that the valve bodyis furnished with a ring-shaped surface which is subjectable to thehydraulic pressure existing in the first power chamber and is,therefore, not pressure-balanced. Therefore, that valve can only performa pressure-limiting function that has a negative bearing on thefunctioning of the vibration absorber. The drawback is particularlyacute in the range of low volumetric flow rates in which a strongtransmission of vibrations takes place from the wheels to the body of anautomotive vehicle which is equipped with such state-of-the-artvibration absorbers.

Therefore, one object of the present invention is to provide a valvearrangement including a valve body that is actuatable by anelectromechanical transducer that improves the functioning of thevibration absorber. The present invention improves the behavior of thevibration absorber and the related desired cushioning comfort,especially in the range of low volumetric flow rates.

SUMMARY OF THE INVENTION

According to the present invention the object of improving vibrationabsorber performance is attained in part because the valve body isdesigned to be pressure-balanced. Also, in a first range of volumetricflow rate the valve body performs a restricting function that depends onthe actuation of the electromechanical transducer. The valve bodysimultaneously interacts with a second, pressure-unbalanced valve bodywhich in a second range of volumetric flow rate influences a secondhydraulic connection through which a unidirectional flow is passed. Inthe traction stage, this second hydraulic connection exists between saidfirst power chamber, on one hand, and said second power chamber jointlywith said balancing chamber, on the other hand. In the thrust stage,this second hydraulic connection exists between said second powerchamber jointly with said first power chamber, on one hand, and saidbalancing chamber, on the other hand. The second valve body performs apressure-limiting function which also depends on the actuation of theelectromechanical transducer during the thrust stage.

The present invention provides the following advantages.

In the range of low vibration absorber speeds and low vibrationabsorbing forces, which are decisive for desirable cushioning comfort, avibration absorber equipped with the inventive valve arrangement is morefinely dosable.

If the electromechanical transducer actuation fails, the vibrationabsorber will remain operative as a passive absorber. By appropriatedesign measures a valve arrangement in accordance with the presentinvention can have one of the potential characteristic curvespreadjusted as the passive characteristic curve of the absorber in theevent of the electromechanical actuation missing or failing.

In contrast with a force-controlled arrangement, the inventive valvearrangement, controlled on the basis of characteristic curves, cantolerate a malfunctioning the electromechanical actuation. For example,signalling times or digitalization errors do not hinder theeffectiveness of the inventive arrangement.

By an expedient shaping of the individual characteristic curves a changeof the position of the vibration absorber valve will be necessaryexclusively in case of a variation of the initiating condition,undulation of the driveway or driving situation. Contrary to this, aforce-depending actuation of the vibration absorber must react to anyvariation of the absorber speed.

A further advantage of the present invention is that the second valvebody is actuatable by a second electromechanical transducer. In thisconjunction it will be particularly expedient if and when said secondvalve body is configured as a part of the second electromechanicaltransducer, for example as the armature of an electromagnet or as a coilsupport of a plunger coil which interacts with a permanent magnet.Optional characteristic curves can be realized with an arrangement ofthis kind, since the restricting and the pressure-limiting functionswill allow to be adjusted independently of each other. For this reason,the inventive valve arrangement is extremely well suited for testpurposes.

In another embodiment according to the present invention, anadvantageous linkage of the restricting function and thepressure-limiting function only is attained when making use of only oneelectromechanical transducer because the second valve body is influencedindirectly through the excursion of the first valve body by theactuation of the electromechanical transducer.

A compact-type design according to one embodiment of the inventive valvearrangement includes the first valve body configured in the shape of abushing being slidingly guided on a stationary cylindrical guideelement. In the latter embodiment, the bushing interacts withcross-sectional areas of flow which are configured in the guide elementand are preferably designed in the shape of slots, particularly asannular grooves. In this conjunction, the second hydraulic connection isformed by a first bore which is configured in the guide element, by acylindrical chamber which accommodates the second valve body and thespring, and by a second bore which is configured in the bushingcoaxially with the first bore.

In another embodiment of the present invention, the second valve body isconfigured in the shape of a ball. The second valve body is prostressedby a spring and interacts with a sealing seat being at one end of thefirst bore. An inventive valve arrangement featuring such aconfiguration is distinguished by a simple design that provides a simplydimensioned "sensing area" at the second valve body.

In accordance with a preferred embodiment of the present invention, thesecond hydraulic connection is formed by cross-sectional areas of flow,for example by slots, bores or annular grooves in the guide element, thesecond valve body designed as a second bushing slidingly guided on theguide element interacting with a sealing seat configured on the guideelement. The sealing seat is preferably a step which has a smaller orlarger diameter. A better splitting-up of the volumetric flow rates willbe rendered possible by this provision. In addition, manufacture of thearrangement is simplified and favorable prerequisites are created for acompensation of the force of flow.

In this context, it will be particularly advantageous for the smoothfunctioning of the inventive valve arrangement of a correspondingvibration absorber if, during the interaction of the first valve bodywith the cross-sectional areas of flow, a compensation of the hydraulicforces turning up in the effective range takes place. This measureaffords the additional advantage of reducing the energy requirements ofthe electromechanical transducer.

The compensation of the forces of flow mentioned before is, for example,attained in that the bushing and/or the chamber which is disposed behindthe cross-sectional areas of flow as seen in the flow direction areconfigured to safeguard a deviation of the volumetric flow. In thiscontext, the front surface of the valve body, designed in the shape of abushing, which interacts with the cross-sectional areas of flowpreferably has a truncated cone-shape.

According to another embodiment of the present invention, the forces offlow are counteracted because the cross-sectional areas of flow end upin an annular hydraulic chamber which is connected to the outlet of thevalve arrangement. In this embodiment, the resulting static pressurewithin the annular chamber effectively induces a hydraulic forcecomponent which counteracts the Bernoulli's forces acting on thebushing.

An inexpensive, space-saving embodiment of the inventive valvearrangement is achieved wherein the first valve body is conceived asbeing a part of the electromechanical transducer. In this embodiment,the electromechanical transducer may either be configured as a plungercoil interacting with a permanent magnet whose coil support is formed bythe first valve body or as an electromagnet whose armature is formed bythe first valve body. The former construction features a more favorabledynamic behavior, whereas the electromagnet used in the latter providesa sturdy assembly which is not susceptible to trouble.

Further embodiments of the present invention include means to guaranteethe functioning of the vibration absorber, equipped with the inventivevalve arrangement, even in case of a failure of the electromechanicaltransducer; means for performing a so-called fail-safe function. Thefail-safe means safeguard a predeterminable mean restricting functionand a predeterminable mean pressure-limiting function in the event of afailure of the electromechanical transducer. In one embodiment, thefirst valve body is, for example, prestressed by a second spring whichcounteracts the spring prestressing the second valve body. In thiscontext, it must be safeguarded that the second hydraulic connectionremains closed in the event of a current failure. Another embodimentincludes means to perform the former function mentioned above whichincludes a third hydraulic connection provided between the inlet and theoutlet of the valve arrangement which is simultaneously released by thefirst valve body when the hydraulic connection is closed by the force ofthe second spring. The use of a simple unidirectionally actingtransducer is rendered possible by this provision.

If, however, the latter-mentioned function is performed, then thefunctioning reliability of the inventive valve arrangement will beincreased since mean forces will occur even at elevated vibrationabsorber speeds. To realize this effect, the hydraulic connection ispartly closed by a third spring which counteracts said spring which actson the first valve body, in which case the electromechanical transducerwill be effective bidirectionally.

In a further advantageous embodiment another possible means to perform afail-safe function of the kind mentioned above consists in that a fourthspring is supported at a force-transmitting element which is actuatableby a third electromechanical transducer. The force-transmitting elementaffords a transmission of the force of the fourth spring to the firstvalve body in the event of a switch-off or a failure of the thirdelectromechanical transducer. This measure constitutes a fail-safeprocess for unidirectionally acting transducers.

In order to achieve a sufficient, more uniform spreading of thecharacteristic curves for small volumetric flow rates, means areprovided in further embodiments that ensure a nonlinear dependence ofthe cross-sectional area of opening of the cross-sectional areas of flowon the excursion of the first valve body. In this instance, the firstvalve body may, for example, be furnished with notches on its frontsurface or with bores in its range interacting with the cross-sectionalareas of flow. As an alternative, the cross-sectional areas of flowwhich are provided in the guide element may also be configured in theshape of bores.

In order to avoid soiling or impurities causing clamping of the valvebodies, one advantageous further development of the subject matter ofthe present invention is that the hydraulic connections are preceded byfilter elements. For example, one filter element is positioned in theguide element before the cross-sectional areas of flow.

Within another advantageous embodiment of the present invention, thefirst valve body is a part of a travel sensor device interacting with acontroller or is coupled to such a device. The controller will generatea correcting variable by comparing the actual position of the firstvalve body to a preselected set position. The corresponding variablebrings about a force of the electromechanical transducer that may exceedthe stationary force required for maintaining the first valve body inthe set position. The dynamics of the inventive valve arrangement will,therefore, be greatly increased.

In order to further reduce the power requirements of theelectromechanical transducer, the first valve body can bepilot-controlled. This provision simultaneously reduces thesusceptibility of the valve arrangement to soiling.

Further details, features and advantages of the present invention willbe revealed by the following description of a total of sevenembodiments, making reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a controllable two-tube vibration absorber equipped withthe inventive valve arrangement in a diagrammatic sectionalrepresentation;

FIG. 2 shows characteristic curves that can be realized with theinventive valve arrangement; and

FIGS. 3, 4A, 4B, 5A, 5B, 6 and 7 respectively show a first to seventhdesign version of the inventive valve arrangement in the sectionalrepresentation corresponding to that in FIG. 1, in an upscaledillustration.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The two-tube vibration absorber 1 which is represented diagrammaticallyin FIG. 1 is comprised of a power cylinder 2 and an external tube 3positioned coaxially with power cylinder 2, so that a storage tank orbalancing chamber 4 which has a circular ring-shaped cross section,partly filled with oil, is formed between them. The interior space ofpower cylinder 2 is subdivided by a piston 6 being slidable by a pistonrod 5 into a first power chamber 7 being configured above the piston 6and a second power chamber 8 being configured beneath the piston.

First power chamber 7 is connected to an inlet 41 of a valve arrangement11 whose outlet 42 is in connection, on one side, with the balancingchamber 4 and, on the other side, through a first non-return valve 9with the second power chamber 8. Furthermore, a hydraulic connection 78is provided which connects the second power chamber 8 through a secondnon-return valve 10 to the first power chamber 7. In the event ofmovement of the piston 6, a flow will occur in one direction onlythrough the valve arrangement 11 which serves for the variation of thecross-sectional area of passage between the first power chamber 7, thesecond power chamber 8, and the balancing chamber 4, respectively,during the traction stage. Similarly a unidirectional flow will occur toeffectively vary the cross-sectional area of flow between the secondpower chamber 8 and the balancing chamber 4 during the thrust stage.

FIG. 2 shows a diagrammatic representation of the characteristic curvesof the vibration absorber shown in FIG. 1; the dependence of thehydraulic pressure existing within the vibration absorber on thevolumetric flow passing through the valve arrangement 11 in the presenceof different ratings of the energizing current which actuates anelectromechanical transducer 14 of the controllable valve arrangement11.

A first embodiment of the inventive valve arrangement 11 which is shownin FIG. 3 comprises a valve housing 39 which accommodates a cylindricalguide element 13 presenting cross-sectional areas of flow 24. Withinguide element 13 a first valve body 12 is slidingly guided and ispositioned to be adjustable by means of electromechanical transducer 14.First valve body 12 is configured in the shape of a tubular bushingwhich interacts with the cross-sectional areas of flow 24. First valvebody 12 defines, within the interior space of guide element 13, acylindrical chamber 19 into which a bore 17, in guide element 13 beneaththe cross-sectional areas of flow 24, and a bore 18, in valve body 12,end up. Sealing seat 20 is at the rear end of the bore 17. A secondvalve body 15 interacts with sealing seat 20. Second valve body 15 isprestressed by a spring 16 taking support at the first valve body 12.Second valve body 15 is a ball in the illustrated example. In thisinstance, the electromechanical transducer 14, for adjusting theposition of first valve body 12, is an electromagnet whose armaturestraddles the first valve body 12. Beyond this, a compression spring 33counteracting the spring 18 is clamped in between the first valve body12 and the bottom of the valve house 39 whose function will be explainedin more detail below.

For the following description of the functioning of the inventive valvearrangement 11 it is initially assumed that the windings of theelectromagnetic transducer 14 are not energized (middle characteristiccurve in FIG. 2) and that the cross-sectional areas of flow 24 which areformed by slots or annular grooves are not covered by the first valvebody 12, thereby providing a hydraulic connection between the inlet 41and the outlet 42 of the valve arrangement. The small volumetric flow(volumetric flow range A in FIG. 2) which is initiated by a slightuniform movement of the piston 6 leads to an increase of the pressurewhich is determined by the opening of the cross-sectional area of flow24 and which acts on the part-surface of second valve body 15 that facesinlet 41. Sealing seat 20, in the guide element 13, will be maintainedclosed by the force of the spring 16 and, when the windings of theelectromagnetic transducer 14 are energized, by the actuating forceexerted by the transducer 14. Sealing seat 20, therefore, remains closeduntil, for example, the resulting pressure from an increase in thevolumetric flow (volumetric flow range B in FIG. 2) overcomes theclosing force which acts on the second valve body 15. The opening of thesealing seat 20 brings about a movement of the bushing-shaped firstvalve body 12 and, consequently, a wider opening of the slots 24.Therefore, the volumetric flow passing through the slots 24 increasesand the pressure ruling at the inlet 41 of the valve arrangement 11subsequently decreases. The described procedure will continue until acondition of equilibrium of forces will exist again at the valve bodies12, 15.

It will be advantageous when the portion of first valve body 12 thatinteracts with the cross-sectional areas of flow (slots) 24 has theshape of a truncated cone. The portion of first valve body 12 having atruncated cone shape is referred to as front surface 26. In this way thevolumetric flow will be deviated during its passage through the slots 24which results in an impulse effect being suited to compensate for theBernoulli's forces that are caused by the flow and which act in theclosing direction of the cross-sectional areas of flow. When the forcegenerated by the electromechanical transducer 14, which preferably actsbidirectionally, changes, the position of the pressure-balanced firstvalve body 12 changes. Simultaneously, the closing force of the secondvalve body 15 which is exerted by the spring 16 varies.

In the de-energized condition of the transducer 14, the cross-sectionalareas of flow 24 are kept partly closed by the action of the compressionspring 33 taking support at the first valve body 12, so that in theevent of a failure of the electromechanical transducer a predeterminablemean restricting function as well as predetermtnable meanpressure-limiting function are maintained.

Another embodiment of the inventive valve arrangement 11 is shown inFIG. 4A. Electromechanical transducer 14 is configured in the shape of aplunger coil 29 interacting with a permanent magnet 28 with the firstvalve body 12 serving simultaneously as a coil support of theprementioned plunger coil 29. The second valve body 15 is formed by atubular bushing 21 which is slidingly guided on the guide element 13.Second valve body 15 interacts with the cross-sectional areas of flow,slots 43, being provided in said guide element 13, and with a sealingseat 22 defined by guide element 13. For flow technique reasons it willbe advantageous in this context when the front surface 44 of the bushing21 has a truncated cone shape. Filter elements 38 are provided in orderto protect the functionally important ranges of the cross-sectionalareas of flow 24, 43 from soiling. FIG. 4A shows one filter element 38arranged upstream of the cross-sectional areas of flow 24.

The chamber 25 which is configurated downstream of the cross-sectionalareas of flow 24 as seen in the direction of flow is preferably shapedto guarantee a deviation of the volumetric flow in order to compensatethe hydraulic forces coming about during the interaction of the firstvalve body 12 with the cross-sectional areas of flow 24. A solution ofthis kind is illustrated in FIG. 4B. In the design version which isshown in FIG. 4B the cross-sectional areas of flow 24 end up in anannular chamber 27. Annual chamber 27 is connected to the outlet 42 ofthe valve arrangement 11 such that the static pressure coming aboutwithin annular chamber 27 will cause a hydraulic force component whichcounteracts the Bernoulli's forces acting on the first valve body 12.

In the embodiment shown in FIG. 5A the electromechanical transducer 14is configured as an electromagnet 30 whose armature 31 forms the firstvalve body 12. The second valve body 15, or bushing 21, is guided on theguide element 13 such that bushing 21 interacts with a radial step 23.Radial step 23 has a larger diameter relative to the outer radius ofguide element 13 and the inner radius of bushing 21. Radial step 23 ispositioned in the range of the cross-sectional areas of flow 43 andforms the sealing seat 22, as illustrated in the lefthand half of FIG.5. As an alternative, an arrangement shown in FIG. 5B will be feasible.In the embodiment illustrated FIG. 5B, the second valve body 15 isconfigured as an armature 47 of a second electromechanical transducer 35which preferably is an electromagnet 45. In this embodiment the spring16 prestressing the first valve body 12, or armature 31, takes supportat a support not identified more closely of the second electromechanicaltransducer 35. The first valve body 12 may be part of a travel sensordevice 40 interacting with a controller (not shown) or may be coupled tosuch a device.

In still another embodiment of the inventive valve arrangement 11 shownin FIG. 6, a second spring 32 is provided between the first valve body12 and the bottom of the valve house 39. Second spring 32 counteractsspring 16 which is positioned between the two valve bodies 12 and 15 andwhose force and spring constant is preselected such that thecross-sectional areas of flow 24 are covered by the first valve body 12.In its lower range,guide element 13 is simultaneously furnished withfurther cross-sectional areas of flow 46 which interact with a controledge 48 defined on first valve body 12. Cross-sectional areas of flow 46afford a third connection between the inlet 41 and the outlet 42. Thethird connection is opened in the event of a failure of theelectromechanical transducer 14 to safeguard a predeterminable meanrestricting function.

FIG. 7 shows another embodiment for safeguarding a predeterminable meanrestricting function and a predeterminable mean pressure-limitingfunction in the event of a failure of the electromechanical transducer14. This embodiment includes a fourth spring 34 which takes support atthe bottom of the valve housing 39. Fourth spring 34 prestresses aforce-transmitting element 37. Element 37 is actuatable, for example, bya third electromechanical or electromagnetic transducer 36. When thethird transducer 36, which is preferably electrically coupled to thefirst transducer 14, is actuated force-transmitting element 37 will bekept at a distance from the first valve body 12. Force-transmittingelement 37 is released in the event of a current failure so the forceexerted by the spring 34 is transmitted to the first valve body 12. Theinteraction of the two springs 16 and 34 maintain valve body 12 in adefined middle position which results in the aforementioned desiredeffect.

Within the framework of the inventive thought it would, moreover, appearreasonable to envisage means ensuring a nonlinear dependence of thecross-sectional area of opening defined by the cross-sectional areas offlow 24 on the excursion of the first valve body 12. For example, valvebody 12 may include notches on its front surface or be furnished withbores in the longitudinal range along valve body 12 interacting with thecross-sectional areas of flow 24. Another possibility consists inconfiguring the cross-sectional areas of flow 24 in the guide element 13in the shape of bores. Further embodiments can, of course, be imaginedin which the first valve body 12 is actuatable by a pilot stage.

It will be apparent to one skilled in the art that the precedingdescription is exemplary rather than limiting in nature. Modificationsare possible without departing from the purview and spirit of thepresent invention, the scope of which is limited only by the appendedclaims.

What is claimed is:
 1. A controllable valve arrangement in acontrollable two-tube vibration absorber having a power cylinder whoseinterior space is subdivided into a first power chamber and a secondpower chamber by means of a slidable piston, and having a balancingchamber partly filled with oil, said valve arrangement, comprising: afirst valve body which is actuatable by an electromechanical transducer,said valve body being prestressed by means of a first spring, said firstvalve body influencing a hydraulic connection through which aunidirectional flow is passed which exists between said first powerchamber, on one hand, and said second power chamber jointly with saidbalancing chamber, on the other hand in a traction stage, theunidirectional flow existing between said first power chamber jointlywith said second power chamber on one hand, and said balancing chamber,on the other hand in a thrust stage, said first valve body beingpressure-balanced such that a first range of volumetric flow rate insaid first valve body performs a restricting function which depends onthe actuation of said electromechanical transducer; and a second valvebody that is pressure-unbalanced such that in a second range ofvolumetric flow rate said second valve body influences a secondhydraulic connection through which a unidirectional flow is passed whichexists between said first power chamber, on one hand, and said secondpower chamber jointly with said balancing chamber, on the other hand, inthe traction stage, the unidirectional flow existing between said secondpower chamber jointly with said first power chamber, on one hand, andsaid balancing chamber, on the other hand in the thrust stage, saidsecond valve body performing a pressure-limiting function that dependson the actuation of said electromechanical transducer.
 2. A valvearrangement as recited in claim 1, wherein said first valve body isdesigned as a part of said electromechanical transducer.
 3. A valvearrangement as recited in claim 2, wherein said electromechanicaltransducer is configured as a plunger coil which interacts with apermanent magnet and whose coil support is formed by said first valvebody.
 4. A valve arrangement as recited in claim 2, wherein saidelectromechanical transducer comprises an electromagnet whose armatureis formed by said first valve body.
 5. A valve arrangement as recited inclaim 1, further comprising a second electromechanical transducer thatactuates said second valve body.
 6. A valve arrangement as recited inclaim 5, wherein said second valve body is designed as a part of saidsecond electromechanical transducer.
 7. A valve arrangement as recitedin claim 1, wherein said second valve body is influenced indirectlythrough the excursion of said first valve body by the actuation of saidelectromechanical transducer.
 8. A valve arrangement as recited in claim7, further comprising means for guaranteeing a predetermined meanrestricting function in the event of a failure of said electromechanicaltransducer.
 9. A valve arrangement as recited in claim 8, furthercomprising a second spring that counteracts said first spring andprestresses said first valve body.
 10. A valve arrangement as recited inclaim 7, further comprising means for safeguarding a predetermined meanrestricting function and a predetermined mean pressure-limiting functionin the event of a failure of said electromechanical transducer.
 11. Avalve arrangement as recited in claim 10, further comprising a thirdspring acting on said first valve body in contrast with said firstspring.
 12. A valve arrangement as recited in claim 11, furthercomprising a fourth spring supported at a force-transmitting elementwhich is actuatable by a second electromechanical transducer and whichaffords a transmission of the force of said fourth spring to said firstvalve body in the event of a failure of said second electromechanicaltransducer.
 13. A valve arrangement as recited in claim 1, wherein saidfirst valve body is coupled to a said second valve body by means of saidspring.
 14. A valve arrangement as recited in claim 1, wherein saidfirst valve body has the shape of a bushing which is slidingly guided ona stationary guide element, such that said bushing interacts with aplurality of cross-sectional areas of flow which are formed on saidguide element.
 15. A valve arrangement as recited in claim 14, whereinsaid cross-sectional areas of flow comprise slots.
 16. A valvearrangement as recited in claim 14, wherein the second hydraulicconnection comprises a first bore formed on said guide element, acylindrical chamber which accommodates said second valve body and saidfirst spring, and by a second bore formed on said bushing coaxially withsaid first bore.
 17. A valve arrangement as recited in claim 16, whereinsaid second valve body is a ball which is prestressed by said firstspring and which interacts with a sealing seat being configured at oneend of said first bore.
 18. A valve arrangement as recited in claim 16,wherein a compensation of hydraulic forces occurs in an effective rangeduring the interaction between said bushing and said cross-sectionalareas of flow.
 19. A valve arrangement as recited in claim 18, furthercomprising an additional chamber positioned downstream of saidcross-sectional areas of flow relative to a flow direction, wherein atleast one of said bushing and said additional chamber are configuredsuch that a minimum deviation of a volumetric flow is maintained.
 20. Avalve arrangement as recited in claim 19, wherein a front surface ofsaid bushing has a truncated-cone shape, said front surface interactingwith said cross-sectional areas of flow.
 21. A valve arrangement asrecited in claim 18, wherein said cross-sectional areas of flow end upin an annular hydraulic chamber which is connected to an outlet of thevalve arrangement such that the static pressure coming about within saidannular chamber causes a hydraulic force component which counteractsBernoulli's forces acting on said bushing.
 22. A valve arrangement asrecited in claim 14, further comprising means for ensuring a nonlineardependence of a cross-sectional area of opening of said cross-sectionalareas of flow on the excursion of said first valve body.
 23. A valvearrangement as recited in claim 22, wherein a front surface of saidfirst valve body is provided with notches.
 24. A valve arrangement asrecited in claim 22, wherein said first valve body is furnished withbores interacting with said cross-sectional areas of flow.
 25. A valvearrangement as recited in claim 22, wherein said cross-sectional areasof flow in said guide element are configured in the shape of bores. 26.A valve arrangement as recited in claim 14, further comprising aplurality of filter elements arranged within said valve assembly suchthat said filter elements precede hydraulic connections.
 27. A valvearrangement as recited in claim 26, wherein one of said filter elementsis positioned in said guide element before said cross-sectional areas offlow.
 28. A valve arrangement as recited in claim 10, further includinga guide element wherein said second hydraulic connection comprises aplurality of cross-sectional areas of flow formed in said guide element,and wherein said second valve body is designed as a bushing which isslidingly guided on said guide element and which interacts with asealing seat being formed on said guide element.
 29. A valve arrangementas recited in claim 28, wherein said sealing seat is formed by a step ofrelatively larger diameter adjacent a smaller diameter in said guideelement.
 30. A valve arrangement as recited in claim 1, wherein saidfirst valve body is part of a travel sensor device interacting with orcoupled to a controller.
 31. A valve arrangement as recited in claim 1,wherein said first valve body is pilot-controlled.